SKF - Rolling Bearings

Materials for rolling bearings
Polyurethane
Polyurethane (PUR) is a wear-resistant organic
material which has good elastic properties. It
withstands operating temperatures from –20
up to +80 °C (–5 to 175 °F). It has good resistance
to mineral oil-based greases, mineral oils
with no or a low proportion of EP additives,
water and water-oil mixtures. It is not
resistant to acids, alkalis or polar solvents.
Lubricants
Capped bearings normally have a factory
grease fill. The lubricant is an integral part of
the bearing. For additional information, refer
to the relevant product chapter.
Coatings
Coating is a well-established method to upgrade
materials and to provide bearings with
additional benefits for specific application conditions.
Two different coating methods developed
by SKF are available and have been
proven successful in many applications.
NoWear is a wear-resistant surface coating
that applies a low-friction carbon coating on
the bearing inner ring raceway(s) and/or the
rolling elements. It can withstand long periods
of operation under marginal lubrication conditions.
For additional information, refer to
NoWear coated bearings († page 1241).
INSOCOAT bearings are standard bearings
that have the external surfaces of their inner
or outer ring plasma-sprayed with an alu minium
oxide to form a coating. It offers resistance
to the damage that can be caused by the
passage of stray electric current through the
bearing. For additional information, refer to
INSOCOAT bearings († page 1205).
Other coatings like zinc chromate, for example,
can offer an alternative to stainless
steel bearings in a corrosive environment,
especially for ready-to-mount bearing units.
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